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Leners Pawn No. 76,776, ma April 14, isos.

IMPROVEMENT IN SLIDE-VALVES VO'(lOMBIlII-ll) HIGH AND LOW-PRESSURIIENGINES.

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IO ALL WHOM IT MAY CONCERN:

Be it known that I, y'InoMas L. Jones, of Natchez, inthe county ofAdams, and'State of Mississippi, have invented a new and improvedGombiucd I-Iigh and Low-Pressure Engine; and I do hereby declare thatthe following is a full, clcu-r, and exact description oftheconstruction and operation of the same, reference being had to theannexed drawings, making a part of this specification, in which- Figure1 is a longitudinal vertical section throughthe steam-chest, and

Figure 2 is a horizontal section through both the steam-chest andcylinder.

This invention relates to that class ot' engines in which the steam, ateach stroke of the piston, is first exhausted to the open air until thesteam-pressure at that end of the cylinder equals the pressure of theair. after which it exhausts to the condenser. v g

The improvementsecnsist in a new arrangement of valves and ports', whichgreatly simplifies the engine, and renders it the most economicalworking engine hitherto constructed.,

In the drawings, A represents thc steam-chest; Bthe cylinder; C, thevalve-rod; D,the piston; E, the piston-rod; F, the pipe, leading Ato thecondenser; and G G', exhausts, leading to the open air, and providedwith air-tight valves, gg', seating downwards. m v is the upper, and mthe lower steamport', the former branchi' ing into two ports, a al, andthe latter into two more, a2 a, all which enter the steam-chest. e e arethc' condenser-ports, andi z" are the exhaust-ports. The steam issuppliedvfronn the boiler to the steam-chest through a pipe, H, whichmay be connected with anylcut-oii` apparatus that it may be thoughtdesirable to use. Of the steam-ports, two, a al, are arranged above, andtwo, a a3, below the middle of the steam-chest.

The condenser-port, e, is between the upper steam-ports, a. al, and thelower condenser-port, e', is between the lower steam-ports, a? a. Oneexhaust, z', is above and near the middle of the steam-chest, and theother, i', is in a corresponding position below.

The valve is a sliding valve, having a` chamber or recess, n, in itsfront side, which connects or disconnccts the ports e, a, and t', and asimilar recess, n', which connects or disconnectsv the ports e', a2, andz". The upper end of the valve, atc, opens or closes the steam-port a,and its lower end, at c, opens or closes the steam; port a3. 1' is thesteam-space, which is constantly full,l of live steam, admitted throughthe pipe Ht Having thus described the arrangement ot thc different partsof my engine, I will now explain its operation.

In order to make such explanation clearer, let us suppose thepiston andvalves to be in the position shown in tig. 2, the piston moving upward,or to the left, as seen in the drawings. -In this position the livesteam will feed through port L3-to the cylinderl below thc piston, andthe steam in the cylinder above the piston will be exhausting throughport al, recess 1t, and condenser-port e. Ports 21., z', a, and e willbe closed, and the coms munication will be so cut off that no steam canget to port zl to escape through it. v

Now, as the piston moves to the left, the valve is moving to the right,and when the piston reaches the end of its stroke, the recesses n and nwill have 'changed so far to the right that the condenser-port e will beclosed, but the steanrport a will still be closed, so that no live steamcan escape through port al, recess n, and exhaust z', which will be inconnect-itam. At the same moment, in the lower end ofthe steam-chest,port ai* will be closed, and port a2 will be put in communication withexhaust t" through the recess n', and in an instant the live steam inthe lower ond of the cylinder will force the valve g up and exhaust tothe open air'until the steam within the cylinder and the air without arebalanced, or, in other words, until the steam in the lowerv end of thecyl# inder is reduced to a pressure ot fifteen pounds to the inch, whenthe valve g will close by its own weight. The next instant, thc valvestill moving to the right, opens port a and lets live steam into thecylinder above the piston, which begins its down stroke. As the valveopens port a, it closes po'rt'al, and severs all communication t'rom'theupper end of the cylinder' to the condenser-port c or the exhaust z';but, at the same time, it opens a communication from the lower end ofthe `cylinder t-o the condenser through port ce, recess n', andcondenserport e", and the steam in the lower end ofthe cylinder, whichhad an instant before been reduced to n. pressure of'i'teen pounds, isnew condensed to a vacirum, when the piston passes down to the end ofvits stroke in the same manner as I have described its passing tothenpper end of the previous stroke from the position in which we firstbeheld it. The piston having arrived at the lower end of its downslt-reke, the saine movement of the parts takes place that I havedescribed as taking place when the piston reached the upper ond ef itsstroke, but in an inverse manner, the movement of the lower ports, z',d2, al, and a3, corresponding to the former movement of the upper ports,a, c, al, and i', and vice versa.

The operation of this mechanism is exceedingly perfect, meeting all theconditions required in a working steam-engine to give it great power,speed, and uniform equable action. It'will be observed that the exhaustend of the cylinder is in connection with the open-air exhaust onlyduring `a small portion of the stroke, and during all the remainder ofthe stroke the open-air exhaust is shut oil` and the-communication isopen from the cylinder to the condenser. It is only necessary to havethe open-air exhaust in connection with the cylinder for a. very brieftime, as thevinner steam-ports and the open-air exhaust-ports are largeand close together, and the passage through the exhaust-pipe may be madeperfectly straight, affording a free escape to the steam when 'inconnection, and the more steam there is to be thus exhausted, thegreater will be its expansive pressure, and

the more rapidly will it escape.

The valves, I ywould so arrange that the condenser shall not he put inconnection with the cylinder when the crank is passing the dead-point,but a moment after, when it has passed twenty or thirty degrees beyondthat part of its revolution. The additional power then imparted to thepiston by the formation of the vacuum in the cylinder, will he thrownupon the crank at s. favorable moment to utilize it toV the utmostextent,` and not to waste it upon the dead-point, as would be the caseotherwise. At the same `time care should be taken that the crank shouldnot pass too far beyond the dead-point before the condensation takesplace, since the ,sooner the increased power is 'applied to'it,thelonger will such power have an opportunity to exert itself upon thepiston. i l

Having thus described my invention, what Iclaim as new, and desire `tosecure by Letters Patent, is The arrangement of the steam-ports a at1 aa3, condenser-ports e e', exhausts z' valves y g', and valve e el c,when the parts referred to are constructed so as to operatesubstantially as andfor the purposes set forth.

THOS. L. JONES.

Witnesses:

Cms. A. Berna', SoLoN C. KEMoN.

